title: Substrate-specific modifications on magnetic iron oxide nanoparticles as an artificial peroxidase for improving sensitivity in glucose detection.
abstract: Magnetic iron oxide nanoparticles (MION) were recently found to act as a peroxidase with intrinsic advantages over natural counterparts. Their limited affinity toward catalysis substrates, however, dramatically reduces their utility. In this paper, some effective groups were screened out and conjugated on MION as substrate-specific modifications for improving MION's affinity to substrates and hence utility. Nanoparticles of four different superficial structures were synthesized and characterized by TEM, size, zeta potential and SQUID, and assayed for peroxidase activity. Glucose detection was selected as an application model system to evaluate the bonus thereof. Catalysis was found to follow Michaelis-Menten kinetics. Sulfhydryl groups incorporated on MION (SH-MION) notably improve the affinity toward a substrate (hydrogen peroxide) and so do amino groups (NH₂-MION) toward another substrate, proved by variation in the determined kinetic parameters. A synergistically positive effect was observed and an apparently elevated detection sensitivity and a significantly lowered detection limit of glucose were achieved when integrated with both sulfhydryl and amino groups (SH-NH₂-MION). Our findings suggest that substrate-specific surface modifications are a straightforward and robust strategy to improve MION peroxidase-like activity. The high activity extends magnetic nanoparticles to wide applications other than glucose detection.
authors.affiliation: Key Laboratory for Green Chemical Process of Ministry of Education, College of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430073, People's Republic of China.
authors.forename: Yanping
authors.initials: Y
authors.lastname: Liu
authors.forename: Faquan
authors.initials: F
authors.lastname: Yu
mesh_terms: D000588:Amines / Q000737:chemistry; D052160:Benzothiazoles / Q000737:chemistry; D002384:Catalysis; D002712:Chlorides / Q000737:chemistry; D019343:Citric Acid / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry; D005296:Ferrous Compounds / Q000737:chemistry; D005947:Glucose / Q000032:analysis* / Q000378:metabolism; D005949:Glucose Oxidase / Q000737:chemistry / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000737:chemistry; D007700:Kinetics; D008280:Magnetics; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D017646:Organosilicon Compounds; D010316:Particle Size; D010544:Peroxidases; D011437:Propylamines; D012821:Silanes / Q000737:chemistry; D013053:Spectrophotometry; D055672:Static Electricity; D013438:Sulfhydryl Compounds / Q000737:chemistry; D013451:Sulfonic Acids / Q000737:chemistry; D013499:Surface Properties
chemical_list: D000588:Amines; D052160:Benzothiazoles; D002712:Chlorides; D005290:Ferric Compounds; D005296:Ferrous Compounds; D058185:Magnetite Nanoparticles; D017646:Organosilicon Compounds; D011437:Propylamines; D012821:Silanes; D013438:Sulfhydryl Compounds; D013451:Sulfonic Acids; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; D019343:Citric Acid; C102833:(3-mercaptopropyl)trimethoxysilane; D006861:Hydrogen Peroxide; D005949:Glucose Oxidase; D010544:Peroxidases; D005947:Glucose; C477625:amino-propyl-triethoxysilane; C029451:ferrous chloride; C024555:ferric chloride